The present invention relates to hair analysis and, more particularly but not exclusively, to a method and an apparatus for illuminating hair for analysis thereof.
Hair dyes and bleach are used to make gray hairs less conspicuous or to dye hair a desired color. Different types of hair dyes exist in the market. One example is a temporary hair dye, such as a color shampoo, a color conditioner, and a color treatment conditioner, which is easy to apply and remains for a short time. Another type of a hair dye is a semi-permanent dye, such as a dye that provides an effect that can be continuously maintained through penetration of an acidic dye into the interior of the hair. A commonly used hair dye is a permanent dye that achieves an essentially permanent dye effect through oxidative polymerization of the dye in the interior of the hair. A particular type of hair dye may be selected depending on the intended use.
Each of these types of dyes is prepared in numerous colors. Usually, a dye color is indicated on the box containing the dye, either by a color number or by means of a sample lock of dyed hair.
However, the color of the dye interacts with the color of the undyed hair. Thus, even where the same colored dye is used, the color of the hair after dyeing differs considerably depending on the natural color, or natural color plus old dye mixture of the hair before dyeing. For example, in a case where the hair before dyeing has a non homogenous mixture of white hair and colored hair, current methods fail to accurately predict the hair color after dyeing. Also, in a case where naturally pigmented hair is dyed with artificial colors, the resulting color depends on the combination of original and artificial pigments already present in the hair.
Consequently, it is difficult to predict the color that will result from dyeing any person's hair solely from the printing on a box or a sample lock of hair, and a problem often arises that the actual color of the hair after dyeing is different from the color anticipated.
Several methods and systems have been developed to predict the final hair color in order to minimize errors and increase customer satisfaction with the use of hair color products. For example, U.S. Pat. No. 6,707,929, filed on Mar. 16, 2004, describes a method and system for analyzing hair and predicting achievable dyed hair colors. The patent describes methods for identifying an achievable hair color based upon at least one starting hair value of a recipient, for identifying a hair coloring agent based upon at least one starting hair value of a recipient, and for outputting an image for a hair color analyzing system. The application further describes a method for providing a hair-coloring product to a consumer. The method comprises the steps of identifying achievable hair colors for the consumer, depicting the achievable colors to the consumer, allowing the consumer to select a desired hair color, and recommending to the consumer a hair-coloring agent to achieve the desired hair color. Another method and system for final hair color prediction is disclosed in U.S. patent application Ser. No. 10/345,249, entitled “Hair color measurement and treatment” to Grossinger, et al., filed on Oct. 1, 2003. This application introduces a system for measuring a reflectance spectrum of a hair sample. The system includes an integrating sphere having a sampling port and an inner surface and a window disposed near the sampling port. The window is placed in close contact with the sample. The system also includes a light source to project light onto the sample via the window and a light detector such as a spectrometer which analyzes light reflected from the inner surface to produce the reflectance spectrum of the sample.
The above methods and systems measure hair color using a spectral-analysis device that comprises a spectral sensor such as a colorimeter or a spectrometer. In use, the color measuring is done by analyzing the light which is reflected from a hair sample positioned in a measuring area in front of the spectral sensor. A light path has to be established between the device and the hair sample in order to ensure accurate measurement of the wavelength of the light which is reflected from the hair sample.
Apart from the light path between the spectral sensor and the hair sample, a light path for illuminating the hair sample has to be established. A considerable effort has been made to provide an accurate illumination subsystem in inspection system architectures that increase the intensity and quantity of light that is effectively available to illuminate image hair samples undergoing inspection. Such illumination subsystems usually comprise flashing units or arrays of light emitting diodes (LEDs), which are directed toward the measuring area. In use, the user of the spectral-analysis device has ensured that the hair sample of the client is in the probed measuring area and thus may wish to view the hair sample itself. The requirements to place the hair sample in the measuring area and to illuminate it may limit the arrangement of hair inspection systems. Moreover, some spectral-analysis devices have to be coupled to the head of the client in order to allow the positioning of the client's hair within the boundaries of the measuring area. In such devices, the user cannot see the hair he is measuring. Such an inability restricts the user's ability to verify that a particular hair sample is positioned in the measuring area and not a bald part of the scalp or another hair sample. This problem arises especially when the client has thinning hair and the positioning of the spectral-analysis device shifts part of the client's hair to outside the measuring area boundaries.
There is thus a widely recognized need for a system and a method that provides a hair inspection process that allows a user to verify whether or not a required hair sample is positioned within the measuring area. Additionally, it would be highly advantageous to have a hair inspection system and method devoid of the above limitations.